momentum...nuff said. heavy boats take longer to accelerate but keep speed when the wind dies. This is why Omegas GP14's and Bosuns do so well at my club

Wetted area, as you said. Consider Merlin Rockets. 30 year-old narrow designs are still competitive against modern MRs on rivers in light conditions. Wide modern hulls plane much faster and more readily and are much quicker on open water.

Combination of momentum and hull & foil shape.

The GP goes well in light stuff, Enterprises even more so. If you look at the hull shape, there's a lot of freeboard and the stern of the boat is not designed around getting the boat planing early.

As a result, in light winds, it is much much easier to get the transom out of the water, which reduces drag massively. Secondly their weight counts in their fvour as they don't decelerate as readily as yout Taser.

Foil shape makes a big difference too - the GP & Ent have relatively short centreboards with a long cord, which gives them a lot of lift at low speed. Your Tasar I suspect will have much longer, narrower foils, which will do absolutely sod all until you get moving above 2-3 knots, at which point they lift like hell.

The trick is to get the stern out of the water and eliminate drag. GP's are utter bandits on handicap though.

Or accelerate either. So that isn't the explanation.

Your argument about lifting the stern is the same as mine: reducing wetted area is especially important at low speed.  

You tend to find that when it's light, there's lots of little zephrys and gusts - the heavy boats do well because they have the momentum which carries them into the next gust. The other problem very light boats like the Tasar have is that they have a habit of accelerating out of the front of the gust & the slower boats sit in it longer.

The argument about boats with lots of rocker is more powerful though - look how well a phantom goes in light winds & look how easy it is to get the stern lifted on those.

+1. Ents at our club could catch some of the the lasers which started 6mins ahead when it was light.

I think the ultimate bandit handicap machine for light winds is a Wineglass.

I don't think I've ever been so angry as the first time I came up against one of those old tubs. I couldn't believe such a barge went so quickly when sailed so badly!

A possible explaination, on top of the hull shape, sail area and carrying power theories could also be the fact that lighter boats are more sensitive to weight movements and punish poor trimming and heavier movements about the boat. Lightwinds on a 5000 is a bit of a dream compared to the 49er, where it seems you have to tip-toe about the boat with silk slippers on........ Reckon the big tubs due to their weight are just more forgiving to movements.

Hull drag has two major components at non-planing speeds - skin friction and wave drag. In light airs, when the hull is not approaching its hull-speed, skin friction predominates, and is proportional to wetted area which is largely down to waterline length and waterline beam. Weight has much less effect on wetted area than on wave drag - if a boat is twice as heavy, you can simply double the draft to double the displacement while hardly affecting the wetted area.

Thus the GP has a larger sail area than a Tasar and probably very little larger wetted area, so in light airs it will be pretty well as fast. Once the wind picks up and wave drag comes into play, and that is proportional to weight, the Tasar will gain the upper hand.

By the way, everybody looks at the all-up weight of the boat when comparing boats , but it is the total displacement that counts for drag, and that comprises the weight of boat plus crew, which makes the ratio of weights for drag purposes between GP & Tasar a lot more even.

http://www.wineglass.org.uk/WINEGLASS%20DINGHY%20MEASUREMENTS.pdf - http://www.wineglass.org.uk/WINEGLASS%20DINGHY%20MEASUREMENT S.pdf

You've defined a minature wineglass.

If I ever see another one, I'm going to go and find the fastest, heaviest, tank-like boat, with a sharp bow I can, (that'll be a Javelin then!) and use it to sink said Wineglass.

Hate 'em

I sailed at Swarkstone when I moved to Derby. Shortly after experiencing that place and the principaI fleet, I swiftly moved on to Staunton Harold. Great Club.

For those not in the know, a Wineglass makes a Wayfarer look dynamic and exciting, yet somehow it seems to go like the clappers in light winds.

If you were to put it in car terms, racing a Laser against one, is a bit like being in your trusty Mk2 Golf GTI and discovering that you're having to work really hard to keep up with a Volvo 240GLT Estate on a twisty wet road. Every time you get an opportunity to overtake it, the thing is so damned big that you can't get past it.

This has brought back traumatic memories - can anyone tell?!

Perhaps it is nothing to do with the boats - maybe you should look at the sailors?

Rick

is that a compliment?

I sail at Burton (in the middle of Swarkstone and Staunton Harold). I have sailed at both Swarkestone and Staunton Harold at open meetings.

I can't stand to sail at Swarkestone with all the islands and shallow patches.

Staunton Harold isn't too bad, but i can't see how the courses can be very good and long when the wind blows over the clubhouse or over the chemical plant. It's just too narrow!!!!

Burton however, great club, great socials and the water is a decent size so you get good long courses in all wind directions.

That's right. PY's are an average of you thrashing the slow boats in the trapezing conditions (or you should be) and then doing the same to you in the light stuff.

Of course, if Laser 2 and other trapeze class sailors only sail in the blowy stuff then the feedback of their results into the PY system won't reflect their need for an easier handicap in light airs, and their PY could even get worse!

1) Read high performance sailing - FB if I remember correctly says light wind (drifting) performance is dominated by sail area versus wet area. These are probably similar for GP and Tasar.

2) Re performing to PY - You are a victim of the PY being an average of all weather conditions.  A tasar and all trap boats go much faster than non-trap boats when powered.  So this lowers the PY.  In comparison, as you have jsut described, the light wind performance is much closer to the those boats with lower overall performance so you won't win on handicap.  (Cherub is a classic extreme example of this - very very slow in the light but uber fast in a breeze.  not a hope of performing "to handicap" in any conditions).

Had to reply to this, having just spent a day in the FD in very light breezes, inland, on windward/leeward courses, racing with a horde of 29er squad sailors.

Now, 29er rates 22 points slower than FD, so not too much in it. Looking at hull shapes, in displacement mode a 29er has about 1/4 the wetted area of an FD and with two 16 year olds aboard is probably about half our all-up weight. Add the windward/leeward course (first two were square with VERY short beat, so no better), and I went on the water thinking we'd be lucky to keep them behind on the water, let alone on handicap. In reality, one 29erbeat us on the water - well done, whoever you were, good bit of yotting - but the rest were very firmly in the rear-view mirror. Admittedly we're known in FD circles as light air specialists, but that's mainly cos we're rubbish in big breeze - too light.

My point is, if you were given a choice of 29er or FD to sail in a must-win race over a windward/leeward in light airs, you'd be mad to pick the FD. The crew makes much more difference in light airs than the handicap of the boat. If you get beat in light airs in your superfast whizzbang class, perhaps you should go out when it's not howling and practice. You can learn a hell of a lot from light airs, and it's amazing how fast you can be in an unsuitable boat.

Neil

According to my rough calcs, the FD probably has 60-70% more skin friction than the 29'er, but only 50% more sail area, so yes Neil, you were on a sticky wicket in the light stuff. Of course, during any little puffs when wave drag started to kick in but the 29'ers still weren't planing, you have the advantage of waterline length.

All of which pretty much confirms your result. But I bet you were more comfortable than the 29'er crews!

I'd say the comfort factor was pretty much the same, it's not that comfy curled up under the vang of an FD. There's far too many fittings in there! Of course, my helm was more comfy than a comfy thing, but that's a price you pay for sailing a boat that rewards so massively upwind in a blow!!

Neil

Waterline length only reduces wave drag (it actually contributes to the skin friction component - more wetted area), and that doesn't become significant until you approach hull speed - something you rarely do in light airs.

Surely Canoes are,like the FD, also at their least competitive on h'cap (in my experience sailing against Messrs Allen and Goodchild) in light airs? Lots of wetted area thanks to the length... At least that's the ony time I could beat them on PY in my old Fireball. Once the wind picked up some, they were gone.

The point I was trying to make was not how slow/fast relative to its handicap the boat is in light airs, but how much difference the way it's sailed makes. It's taken us several years to make the FD go in light airs, it's really very much easier in a good F3. If you get beat by a particular boat in light airs, might it not be that they are sailing better than you? The current obsession with the "adrenaline junkie" end of the wind range means that lots of sailors don't bother with the light stuff at all. No wonder they get their butts kicked when they do! I still think any trapeze assymetric "should" have the legs of the FD on a windward/leeward in the light - due to the FD being slightly underpowered downwind, as well as the weight and wetted area issues. Light airs are just as much of a challenge as 30 knots, it's just a different kind of challenge. The people who are really good at it (not me, barely adequate would best describe me) can make almost any boat a light air bandit.

Neil

Neil, I'd say it's more comfy curled up down to leeward in a FD than any boat I would care to name, at least you can lay down in the leeward hole and be generally out of the eay without being in the way of everything. Crews of these new fangled boats make it look like they are tying to stand up on top of a beach ball when they are not on the wire.

That's a very good way of putting the effect of sailing a boat with a high floor. I've always likened it to standing on the lid of a tea chest (removing the lid and standing down on the base being the analogy for a boat without a double floor, like a 505), but yeah, beach ball, I like it...